usb: chipidea: udc: otg_set_peripheral is useless for some chipidea users

It is useless at below cases:
- If we implement both usb host and device at chipidea driver.
- If we don't need phy->otg.

Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>